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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // Low-latency audio capturing class utilizing audio input stream provided | 5 // Low-latency audio capturing class utilizing audio input stream provided |
6 // by a server (browser) process by use of an IPC interface. | 6 // by a server (browser) process by use of an IPC interface. |
7 // | 7 // |
8 // Relationship of classes: | 8 // Relationship of classes: |
9 // | 9 // |
10 // AudioInputController AudioInputDevice | 10 // AudioInputController AudioInputDevice |
11 // ^ ^ | 11 // ^ ^ |
12 // | | | 12 // | | |
13 // v IPC v | 13 // v IPC v |
14 // AudioInputRendererHost <---------> AudioInputIPCDelegate | 14 // AudioInputRendererHost <---------> AudioInputIPCDelegate |
15 // ^ (impl in AudioInputMessageFilter) | 15 // ^ (impl in AudioInputMessageFilter) |
16 // | | 16 // | |
17 // v | 17 // v |
18 // AudioInputDeviceManager | 18 // AudioInputDeviceManager |
19 // | 19 // |
20 // Transportation of audio samples from the browser to the render process | 20 // Transportation of audio samples from the browser to the render process |
21 // is done by using shared memory in combination with a SyncSocket. | 21 // is done by using shared memory in combination with a SyncSocket. |
22 // The AudioInputDevice user registers an AudioInputDevice::CaptureCallback by | 22 // The AudioInputDevice user registers an AudioInputDevice::CaptureCallback by |
23 // calling Initialize(). The callback will be called with recorded audio from | 23 // calling Initialize(). The callback will be called with recorded audio from |
24 // the underlying audio layers. | 24 // the underlying audio layers. |
25 // The session ID is used by the AudioInputRendererHost to start the device | 25 // The session ID is used by the AudioInputRendererHost to start the device |
26 // referenced by this ID. | 26 // referenced by this ID. |
27 // | 27 // |
28 // State sequences: | 28 // State sequences: |
29 // | 29 // |
30 // Sequence where session_id has not been set using SetDevice(): | |
31 // ('<-' signifies callbacks, -> signifies calls made by AudioInputDevice) | |
32 // Start -> InitializeOnIOThread -> CreateStream -> | 30 // Start -> InitializeOnIOThread -> CreateStream -> |
33 // <- OnStreamCreated <- | 31 // <- OnStreamCreated <- |
34 // -> StartOnIOThread -> PlayStream -> | 32 // -> StartOnIOThread -> PlayStream -> |
35 // | 33 // |
36 // Sequence where session_id has been set using SetDevice(): | |
37 // Start -> InitializeOnIOThread -> StartDevice -> | |
38 // <- OnDeviceReady <- | |
39 // -> CreateStream -> | |
40 // <- OnStreamCreated <- | |
41 // -> StartOnIOThread -> PlayStream -> | |
42 // | 34 // |
43 // AudioInputDevice::Capture => low latency audio transport on audio thread => | 35 // AudioInputDevice::Capture => low latency audio transport on audio thread => |
44 // | | 36 // | |
45 // Stop --> ShutDownOnIOThread ------> CloseStream -> Close | 37 // Stop --> ShutDownOnIOThread ------> CloseStream -> Close |
46 // | 38 // |
47 // This class depends on two threads to function: | 39 // This class depends on two threads to function: |
48 // | 40 // |
49 // 1. An IO thread. | 41 // 1. An IO thread. |
50 // This thread is used to asynchronously process Start/Stop etc operations | 42 // This thread is used to asynchronously process Start/Stop etc operations |
51 // that are available via the public interface. The public methods are | 43 // that are available via the public interface. The public methods are |
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86 : NON_EXPORTED_BASE(public AudioCapturerSource), | 78 : NON_EXPORTED_BASE(public AudioCapturerSource), |
87 NON_EXPORTED_BASE(public AudioInputIPCDelegate), | 79 NON_EXPORTED_BASE(public AudioInputIPCDelegate), |
88 NON_EXPORTED_BASE(public ScopedLoopObserver) { | 80 NON_EXPORTED_BASE(public ScopedLoopObserver) { |
89 public: | 81 public: |
90 AudioInputDevice(AudioInputIPC* ipc, | 82 AudioInputDevice(AudioInputIPC* ipc, |
91 const scoped_refptr<base::MessageLoopProxy>& io_loop); | 83 const scoped_refptr<base::MessageLoopProxy>& io_loop); |
92 | 84 |
93 // AudioCapturerSource implementation. | 85 // AudioCapturerSource implementation. |
94 virtual void Initialize(const AudioParameters& params, | 86 virtual void Initialize(const AudioParameters& params, |
95 CaptureCallback* callback, | 87 CaptureCallback* callback, |
96 CaptureEventHandler* event_handler) OVERRIDE; | 88 int session_id) OVERRIDE; |
97 virtual void Start() OVERRIDE; | 89 virtual void Start() OVERRIDE; |
98 virtual void Stop() OVERRIDE; | 90 virtual void Stop() OVERRIDE; |
99 virtual void SetVolume(double volume) OVERRIDE; | 91 virtual void SetVolume(double volume) OVERRIDE; |
100 virtual void SetDevice(int session_id) OVERRIDE; | |
101 virtual void SetAutomaticGainControl(bool enabled) OVERRIDE; | 92 virtual void SetAutomaticGainControl(bool enabled) OVERRIDE; |
102 | 93 |
103 protected: | 94 protected: |
104 // Methods called on IO thread ---------------------------------------------- | 95 // Methods called on IO thread ---------------------------------------------- |
105 // AudioInputIPCDelegate implementation. | 96 // AudioInputIPCDelegate implementation. |
106 virtual void OnStreamCreated(base::SharedMemoryHandle handle, | 97 virtual void OnStreamCreated(base::SharedMemoryHandle handle, |
107 base::SyncSocket::Handle socket_handle, | 98 base::SyncSocket::Handle socket_handle, |
108 int length, | 99 int length, |
109 int total_segments) OVERRIDE; | 100 int total_segments) OVERRIDE; |
110 virtual void OnVolume(double volume) OVERRIDE; | 101 virtual void OnVolume(double volume) OVERRIDE; |
111 virtual void OnStateChanged( | 102 virtual void OnStateChanged( |
112 AudioInputIPCDelegate::State state) OVERRIDE; | 103 AudioInputIPCDelegate::State state) OVERRIDE; |
113 virtual void OnDeviceReady(const std::string& device_id) OVERRIDE; | |
114 virtual void OnIPCClosed() OVERRIDE; | 104 virtual void OnIPCClosed() OVERRIDE; |
115 | 105 |
116 friend class base::RefCountedThreadSafe<AudioInputDevice>; | 106 friend class base::RefCountedThreadSafe<AudioInputDevice>; |
117 virtual ~AudioInputDevice(); | 107 virtual ~AudioInputDevice(); |
118 | 108 |
119 private: | 109 private: |
120 // Methods called on IO thread ---------------------------------------------- | 110 // Methods called on IO thread ---------------------------------------------- |
121 // The following methods are tasks posted on the IO thread that needs to | 111 // The following methods are tasks posted on the IO thread that needs to |
122 // be executed on that thread. They interact with AudioInputMessageFilter and | 112 // be executed on that thread. They interact with AudioInputMessageFilter and |
123 // sends IPC messages on that thread. | 113 // sends IPC messages on that thread. |
124 void InitializeOnIOThread(); | 114 void InitializeOnIOThread(); |
125 void SetSessionIdOnIOThread(int session_id); | |
126 void StartOnIOThread(); | 115 void StartOnIOThread(); |
127 void ShutDownOnIOThread(); | 116 void ShutDownOnIOThread(); |
128 void SetVolumeOnIOThread(double volume); | 117 void SetVolumeOnIOThread(double volume); |
129 void SetAutomaticGainControlOnIOThread(bool enabled); | 118 void SetAutomaticGainControlOnIOThread(bool enabled); |
130 | 119 |
131 // MessageLoop::DestructionObserver implementation for the IO loop. | 120 // MessageLoop::DestructionObserver implementation for the IO loop. |
132 // If the IO loop dies before we do, we shut down the audio thread from here. | 121 // If the IO loop dies before we do, we shut down the audio thread from here. |
133 virtual void WillDestroyCurrentMessageLoop() OVERRIDE; | 122 virtual void WillDestroyCurrentMessageLoop() OVERRIDE; |
134 | 123 |
135 AudioParameters audio_parameters_; | 124 AudioParameters audio_parameters_; |
136 | 125 |
137 CaptureCallback* callback_; | 126 CaptureCallback* callback_; |
138 CaptureEventHandler* event_handler_; | |
139 | 127 |
140 AudioInputIPC* ipc_; | 128 AudioInputIPC* ipc_; |
141 | 129 |
142 // Our stream ID on the message filter. Only modified on the IO thread. | 130 // Our stream ID on the message filter. Only modified on the IO thread. |
143 int stream_id_; | 131 int stream_id_; |
144 | 132 |
145 // The media session ID used to identify which input device to be started. | 133 // The media session ID used to identify which input device to be started. |
146 // Only modified on the IO thread. | 134 // Only modified in Initialize() and ShutDownOnIOThread(). |
147 int session_id_; | 135 int session_id_; |
148 | 136 |
149 // State variable used to indicate it is waiting for a OnDeviceReady() | |
150 // callback. Only modified on the IO thread. | |
151 bool pending_device_ready_; | |
152 | |
153 // Stores the Automatic Gain Control state. Default is false. | 137 // Stores the Automatic Gain Control state. Default is false. |
154 // Only modified on the IO thread. | 138 // Only modified on the IO thread. |
155 bool agc_is_enabled_; | 139 bool agc_is_enabled_; |
156 | 140 |
157 // Our audio thread callback class. See source file for details. | 141 // Our audio thread callback class. See source file for details. |
158 class AudioThreadCallback; | 142 class AudioThreadCallback; |
159 | 143 |
160 // In order to avoid a race between OnStreamCreated and Stop(), we use this | 144 // In order to avoid a race between OnStreamCreated and Stop(), we use this |
161 // guard to control stopping and starting the audio thread. | 145 // guard to control stopping and starting the audio thread. |
162 base::Lock audio_thread_lock_; | 146 base::Lock audio_thread_lock_; |
163 AudioDeviceThread audio_thread_; | 147 AudioDeviceThread audio_thread_; |
164 scoped_ptr<AudioInputDevice::AudioThreadCallback> audio_callback_; | 148 scoped_ptr<AudioInputDevice::AudioThreadCallback> audio_callback_; |
165 | 149 |
166 DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice); | 150 DISALLOW_IMPLICIT_CONSTRUCTORS(AudioInputDevice); |
167 }; | 151 }; |
168 | 152 |
169 } // namespace media | 153 } // namespace media |
170 | 154 |
171 #endif // MEDIA_AUDIO_AUDIO_INPUT_DEVICE_H_ | 155 #endif // MEDIA_AUDIO_AUDIO_INPUT_DEVICE_H_ |
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